A window of the team bus was damaged after an explosion before the AS Monaco fixture (Picture: AP Photo/Martin Meissner)

The bomb attack on Borussia Dortmund’s team bus could have been inspired by Islamist terror, reports claim.

Police are understood to be investigating a possible link after discovering a letter near the scene of the three explosions as the Dortmund squad were heading to Signal Iduna Park for a Champion;s League game.

According to Suddeutsche Zeitung and German press agency Dpa, theletter referred to 2016’s attack on a Berlin market which was carried out by an ISIS-inspired terrorist and the fact that German surveillance aircraft are being used in Syria.

The letter reportedly written in German began: ‘In the Name of Allah, Most Gracious, Most Merciful.’

The attack left Dortmund defender Marc Bartra requiring surgery on a broken bone in his wrist.

Three explosions took place as the bus left for Signal Iduna Park (Picture: EPA/STR)

A police van outside the stadium as fans leave the abandoned game (Picture: Matt West/BPI)

The newspaper quoting security sources stressing that the letter and any Islamist link had not yet been been verified.

German federal prosecutors, who usually investigate serious crimes including terrorism, are leading the probe.
Police are also looking at the authenticity of a second letter claiming responsibility which, it said, could have come from anti-fascists.